1821566880 has 672 divisors, whose sum is σ = 7773905664. Its totient is φ = 394149888.

The previous prime is 1821566863. The next prime is 1821566897. The reversal of 1821566880 is 886651281.

1821566880 is a `hidden beast` number, since 1 + 8 + 2 + 1 + 566 + 8 + 80 = 666.

It is an interprime number because it is at equal distance from previous prime (1821566863) and next prime (1821566897).

It is a tau number, because it is divible by the number of its divisors (672).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 111 ways as a sum of consecutive naturals, for example, 18778992 + ... + 18779088.

It is an arithmetic number, because the mean of its divisors is an integer number (11568312).

Almost surely, 2^1821566880 is an apocalyptic number.

1821566880 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1821566880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3886952832).

1821566880 is an abundant number, since it is smaller than the sum of its proper divisors (5952338784).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1821566880 is an equidigital number, since it uses as much as digits as its factorization.

1821566880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 160 (or 137 counting only the distinct ones).

The product of its (nonzero) digits is 184320, while the sum is 45.

The square root of 1821566880 is about 42679.8181814309. The cubic root of 1821566880 is about 1221.2794246062.

The spelling of 1821566880 in words is "one billion, eight hundred twenty-one million, five hundred sixty-six thousand, eight hundred eighty".